Upgrade surefire

Add second execution block to run tests with true MultiRelease jar

Author: rfscholte

plexus-java/pom.xml

@@ -22,7 +22,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-surefire-plugin</artifactId>
-          <version>2.20</version>
+          <version>2.21.0</version>
         </plugin>
       </plugins>
     </pluginManagement>
@@ -130,6 +130,24 @@
                 </execution>
               </executions>
             </plugin>
+            <!-- Reuse unittest configuration, now run it as true Multi Release jar -->
+            <plugin>
+              <groupId>org.apache.maven.plugins</groupId>
+              <artifactId>maven-surefire-plugin</artifactId>
+              <executions>
+                <execution>
+                  <id>jdk9</id>
+                  <phase>integration-test</phase>
+                  <goals>
+                    <goal>test</goal>
+                  </goals>
+                  <configuration>
+                    <!-- force new configuration, otherwise surefire won't run a second time -->
+                    <failIfNoTests>true</failIfNoTests>
+                  </configuration>
+                </execution>
+              </executions>
+            </plugin>
           </plugins>
         </pluginManagement>
       </build>